1. Technical Field
The present invention relates to a liquid crystal device in which a liquid crystal is held between a pair of substrates, and a projection-type display device which uses the liquid crystal device as a light valve.
2. Related Art
In a liquid crystal device, an element substrate provided with an image display region in which a plurality of pixel electrodes are arranged, at one surface side, and an opposing substrate provided with a common electrode to which a common potential is applied are bonded by a sealing material, and a liquid crystal layer is held within a region surrounded by the sealing material between the element substrate and the opposing substrate. In such a liquid crystal device, when ionic impurities eluted from ionic impurities or sealing materials mixed at the time of liquid crystal injection are agglomerated within an image display region by driving of the liquid crystal device, deterioration of the display quality such as burn-in (spot) of an image is caused. Consequently, a technique is proposed which prevents ionic impurities from being agglomerated within the image display region by providing a peripheral electrode in the outside of the image display region, and attracting and retaining ionic impurities in the peripheral electrode (see JP-A-2008-58497).
Specifically, in FIG. 4 and the like of the technique of JP-A-2008-58497, a first peripheral electrode and a second peripheral electrode are provided so as to surround the periphery of the image display region between the image display region and a horizontal transfer circuit (driving circuit portion), and between the image display region and a vertical transfer circuit (driving circuit portion). Therefore, when different potentials are applied to the first peripheral electrode and the second peripheral electrode, and the polarities of the potentials applied to the first peripheral electrode and the second peripheral electrode are reversed for each frame, a horizontal electric field is generated between the first peripheral electrode and the second peripheral electrode, and thus ionic impurities are attracted into the first peripheral electrode and the second peripheral electrode, and are retained therein.
However, when the peripheral electrodes (first peripheral electrode and second peripheral electrode) are extended along the sealing material, a trapping electrical supply line that supplies a potential for ionic impurity trapping to the peripheral electrodes intersects a signal line provided in the driving circuit portions (horizontal transfer circuit and vertical transfer circuit), or a signal line extending toward the driving circuit portions. For this reason, there is a problem that when an alternating current is applied to the peripheral electrodes, the waveform distortion and the like are generated in a signal flowing through the signal line and the display quality is deteriorated due to capacitive coupling between the signal lines provided in the driving circuit portions, or the signal lines extending toward the driving circuit portions.